From 4dbf1ee2bd645b8e6170f608e60ffaa714f29a71 Mon Sep 17 00:00:00 2001
From: Jason Turner <jason@emptycrate.com>
Date: Sat, 23 Apr 2016 22:12:08 -0600
Subject: [PATCH] Pull out Return_Optimizer

---
 .../chaiscript/language/chaiscript_engine.hpp |  4 +-
 .../language/chaiscript_optimizer.hpp         | 39 ++++++++++++++++++-
 .../chaiscript/language/chaiscript_parser.hpp | 31 +--------------
 3 files changed, 41 insertions(+), 33 deletions(-)

diff --git a/include/chaiscript/language/chaiscript_engine.hpp b/include/chaiscript/language/chaiscript_engine.hpp
index d4fce2d..2716127 100644
--- a/include/chaiscript/language/chaiscript_engine.hpp
+++ b/include/chaiscript/language/chaiscript_engine.hpp
@@ -219,7 +219,7 @@ namespace chaiscript
                std::vector<std::string> t_modulepaths = std::vector<std::string>(),
                       std::vector<std::string> t_usepaths = std::vector<std::string>())
       : m_module_paths(std::move(t_modulepaths)), m_use_paths(std::move(t_usepaths)),
-        m_parser(std::make_unique<parser::ChaiScript_Parser<optimizer::For_Loop_Optimizer>>())
+        m_parser(std::make_unique<parser::ChaiScript_Parser<optimizer::Optimizer<optimizer::Return_Optimizer, optimizer::For_Loop_Optimizer>>>())
     {
       if (m_module_paths.empty())
       {
@@ -244,7 +244,7 @@ namespace chaiscript
     ChaiScript( std::vector<std::string> t_modulepaths = std::vector<std::string>(),
                       std::vector<std::string> t_usepaths = std::vector<std::string>())
       : m_module_paths(std::move(t_modulepaths)), m_use_paths(std::move(t_usepaths)),
-        m_parser(std::make_unique<parser::ChaiScript_Parser<optimizer::For_Loop_Optimizer>>())
+        m_parser(std::make_unique<parser::ChaiScript_Parser<optimizer::Optimizer<optimizer::Return_Optimizer, optimizer::For_Loop_Optimizer>>>())
     {
       if (m_module_paths.empty())
       {
diff --git a/include/chaiscript/language/chaiscript_optimizer.hpp b/include/chaiscript/language/chaiscript_optimizer.hpp
index 8d1173b..8fc10d8 100644
--- a/include/chaiscript/language/chaiscript_optimizer.hpp
+++ b/include/chaiscript/language/chaiscript_optimizer.hpp
@@ -13,6 +13,20 @@
 namespace chaiscript {
   namespace optimizer {
 
+    template<typename ... T>
+      struct Optimizer : T...
+    {
+      Optimizer() = default;
+      Optimizer(T ... t)
+        : T(std::move(t))...
+      {
+      }
+
+      AST_NodePtr optimize(AST_NodePtr p) {
+        (void)std::initializer_list<int>{ (p = T::optimize(p), 0)... };
+        return p;
+      }
+    };
 
     template<typename T>
       auto child_at(const T &node, const size_t offset) {
@@ -35,9 +49,32 @@ namespace chaiscript {
     template<typename T>
       AST_NodePtr make_compiled_node(const AST_NodePtr &original_node, std::vector<AST_NodePtr> children, T callable)
       {
-        return chaiscript::make_shared<AST_Node, eval::Compiled_AST_Node>(original_node, children, std::move(callable));
+        return chaiscript::make_shared<AST_Node, eval::Compiled_AST_Node>(original_node, std::move(children), std::move(callable));
       }
 
+
+    struct Return_Optimizer {
+      AST_NodePtr optimize(const AST_NodePtr &p)
+      {
+        if (p->identifier == AST_Node_Type::Def
+            && !p->children.empty())
+        {
+          auto &last_child = p->children.back();
+          if (last_child->identifier == AST_Node_Type::Block) {
+            auto &block_last_child = last_child->children.back();
+            if (block_last_child->identifier == AST_Node_Type::Return) {
+              if (block_last_child->children.size() == 1) {
+                last_child->children.back() = block_last_child->children[0];
+              }
+            }
+          }
+        }
+
+        return p;
+      }
+    };
+
+
     struct For_Loop_Optimizer {
       AST_NodePtr optimize(const AST_NodePtr &for_node) {
 
diff --git a/include/chaiscript/language/chaiscript_parser.hpp b/include/chaiscript/language/chaiscript_parser.hpp
index e41bd7e..0b5af4b 100644
--- a/include/chaiscript/language/chaiscript_parser.hpp
+++ b/include/chaiscript/language/chaiscript_parser.hpp
@@ -318,35 +318,6 @@ namespace chaiscript
         }
       }
 
-      /// Returns the front-most AST node
-
-
-      static void optimize_returns(AST_NodePtr &p)
-      {
-        for (auto &c : p->children)
-        {
-          if (c->identifier == AST_Node_Type::Def && c->children.size() > 0) {
-            auto &last_child = c->children.back();
-            if (last_child->identifier == AST_Node_Type::Block) {
-              auto &block_last_child = last_child->children.back();
-              if (block_last_child->identifier == AST_Node_Type::Return) {
-                if (block_last_child->children.size() == 1) {
-                  block_last_child = block_last_child->children[0];
-                }
-              }
-            }
-          }
-          optimize_returns(c);
-        }
-      }
-
-
-      AST_NodePtr ast(bool t_optimize_returns = true) {
-        auto ptr = m_match_stack.front();
-        if (t_optimize_returns) { optimize_returns(ptr); }
-        return ptr;
-      }
-
 
       /// Helper function that collects ast_nodes from a starting position to the top of the stack into a new AST node
       template<typename NodeType>
@@ -2383,7 +2354,7 @@ namespace chaiscript
           m_match_stack.push_back(chaiscript::make_shared<AST_Node, eval::Noop_AST_Node>());
         }
 
-        return ast();
+        return m_match_stack.front();
       }
     };
   }